Plasmin activator inhibitor-1 (PAI-1) activity

General Information

Plasminogen activator inhibitor 1 (Pai-1) is a single-chain glycoprotein with a weight of 47 kDa. It belongs to a family of proteins that inhibit (block) plasminogen activators. In the process of fibrinolysis, tissue plasminogen activator converts inactive plasminogen into active plasmin. Plasmin participates in fibrin degradation, and also provides local protease activity in a number of physiological processes, such as ovulation, cell migration, and epithelial cell differentiation processes.

Pai-1 is a pivotal inhibitor of tissue and other plasminogen activators. It limits the production of plasmin and thereby controls fibrinolysis. Uncontrolled production of plasmin can accelerate fibrin degradation and increase the risk of bleeding. Pai-1 levels are partly controlled on a genetic basis. Some polymorphisms of the Pai-1 gene lead to an increase in the concentration of Pai-1 in the blood. Elevated Pi-1 levels in the blood are associated with a number of atherosclerotic risk factors. Insulin and proinsulin also correlate with Pi-1 concentrations. Patients with diabetes and insulin resistance tend to have increased levels of Pi-1.

Pai-1 is a thrombotic factor in both arterial and venous thromboembolic diseases. An increase in the concentration of Pai-1 is associated with a higher risk of coronary syndrome in patients with chronic and acute coronary artery diseases.

Important information: Plasminogen activator inhibitor is an acute-phase reactive substance, so its transient increase is possible during inflammation, infection or trauma. Its level also increases during pregnancy.

Study material: Venous blood